The invention relates to an arrangement of two fuselage sections of an aircraft and a connecting structure for connecting fuselage skins.
Documents US-A-3 600 016, EP-A-0 048 191, EP-A-1 127 785 and GB-A-2 074 117 disclose a coupling element comprising a base flange for connecting two longitudinal stiffening elements of an fuselage to be connected.
Modern aircraft and in particular passenger aircraft are nowadays predominantly constructed in a sectional construction method. In this arrangement a multitude of pre-fabricated barrel-like fuselage sections are joined, so as to form circumferential transverse seams, to form the complete aircraft fuselage. Each fuselage section comprises a multitude of annular frame elements, which are preferably arranged one behind the other so as to be evenly spaced apart, which are clad with a circumferential fuselage skin. For further stiffening of the fuselage section, in each case between two annular frame elements a multitude of longitudinal stiffening elements are connected to the fuselage skin. The longitudinal stiffening elements, which as a rule are so-called stringers or stringer profiles, in each case essentially extend so as to be parallel to the longitudinal axis of the fuselage section and are arranged on the inside, circumferentially on the fuselage section, so as to be evenly spaced apart from each other. The longitudinal stiffening elements or stringer profiles, which in each case extend parallel to each other, can comprise a Z-shaped, an L-shaped, an Ω-shaped or some other cross-sectional geometry. The fuselage skin, the annular frame elements and the longitudinal stiffening elements can comprise aluminium alloy material, a fibre-reinforced plastic material, for example a carbon-fibre-reinforced epoxy resin, or a combination of the above-mentioned materials in a hybrid construction. The connection of two fuselage sections so as to in each case form a circumferential transverse seam requires a multitude of further components.
The fuselage skins are first connected, preferably so as to abut, with a transverse splicing plate that is at least circumferential in some regions. A circumferential annular frame element positioned in the region of the transverse seam is joined, by means of a multitude of cleats circumferentially arranged on the annular frame element, to the transverse splicing plate and to at least one of the two abutting fuselage skins. The remaining annular frame elements outside the transverse seam regions of the fuselage section can also be connected to the fuselage skin by means of such cleats. The opposing stringers in the region of a transverse seam are connected to a multitude of stringer couplings. Furthermore, in the joining technology that is presently used for the transverse butt joining of two fuselage sections, a multitude of support elements are provided by means of which support elements support is provided to the annular frame element in the transverse seam region to prevent tilting in relation to the fuselage skin. All the components mentioned need to be precisely positioned relative to the structural elements of the fuselage sections to be connected, and also need to be very precisely drilled and firmly joined by means of suitable connecting elements. Moreover, in particular a number of angle brackets and stringer couplings are to be provided and installed for each transverse abutting joint between two fuselage sections, which number as a rule corresponds to the number of stringers installed in the fuselage section. In this arrangement it must be taken into account in addition that the number of stringers required for stiffening a fuselage section generally-speaking increases proportionally to their cross-sectional dimensions so that the installation effort in fuselages of large cross-sectional dimensions increases considerably. Furthermore, all the holes need to be subjected to expensive sealing procedures and corrosion protection procedures.
Depending on the types of materials used in the fuselage sections to be joined, possible connecting elements are, for example, rivet elements or screws. As an alternative, thermal joining methods can be used. As an alternative, fibre-reinforced plastic materials can be joined with the use of adhesive connections so that there is no need to fabricate attachment holes.